380 GENEEAL HISTOEY OF THE II4FTJS0EIA. 



Fam. 8. Aphthonia. — Surface ciliated, and furnished besides with filaments. 



Fam. 9. Decteria. — Mouth provided with a circlet of bristles ; in three genera lateral, in 



two anterior in position. 

 Fam. 10. CiNETOCHiLiNA. — Mouth on the upper surface, furnished with a vibrating flap. 



Cilia in longitudinal lines. 

 Fam. 11. Apionidina (in part the Enchelia, Ehr., and the Parameciens, Bicj.). — Bodies 



small, soft, thicker at one end than the other ; cilia in longitudinal 



rows. Mouth, where perceptible, at the anterior extremity. 

 Fam. 12. Tapinia. — Cilia scattered, or collected in particiilar spots, but never in rows. 



Body usually very small. Mouth only proved to exist by means of 



artificial feeding. 

 Fam. 13. Trachblina. — Body elongated into a neck-like anterior process, or a laterally 



curved trunk. 

 Fam. 14. Oxytrichina. — Equal the Keroniens of Dujardin. 



2. Parasitical forms, with or without a mouth, Tnostly receiving only the juices of 

 other animals. 



Fam. 15. Cobalina. — Body mostly flattened, oval, elliptic or reniform, covered by numer- 

 ous rows of fine cilia, and oftentimes with jointed cilia on the under 

 surface. A raised margin or hollow fold occupied by cilia often 

 indicates the mouth, of which, however, in several cases, no trace is 

 evident. The animalcules commonly live internally, upon the juices 

 of other beings, and occasionally on their outer siu'face, in which case 

 the food they take is soHd. They present among themselves numerous 

 peculiarities and points of agreement, and at the same time many 

 anomalies, and are lower in the scale than free living forms similar to 

 them, e.g. Oxytrichina; their movements are rather automatic. The 

 genera included are, Alastor (Kerona, Ehr.), Plagiotoma, Leucophrys, 

 and Opalina. 

 B. General covering firm by induration of the integument, or by excretion of hard 

 granules. 



Fam. 16. Euplotina. — Equal the Ploesconiens of Dujardin. 



Fam. 17. Colepina. — Represented by the genus Coleps (Ehr.). 



C. Metabolica. — Very contractile ; undergoing protean alterations of their figure through 

 a contraction and extension of the body. Cilia scarcely observable on 

 the body at large, but collected on the neck-like process. 



Fam. 18. Ophryocercina (Ehr.), including also Trachelocerca and Phialina. 



FAMILY I.— ICHTHYDINA. 

 (Plates XXY. 357, 358. Plate XXXI. 28, 29, 31.) 

 This family, which in our arrangement forms a subgroup of Ciliata, con- 

 stituted in Ehrenberg's system a section of Eotatoria, — an association which 

 cannot be maintained now that theii' more intimate and essential organiza- 

 tion is known. Indeed, these beings seem to have received but little atten- 

 tion from that great naturalist, who had only an imperfect accoimt of them 

 to offer. They were described as Rotatoria with a single continuous rotary 

 organ, not cut or lobed at the margin, and without lorica or shell. Four 

 genera were enumerated — viz. Ptggura, Iclithydium, Chcetonotus, and Gleno- 

 pliora. Their relative peculiarities were thus stated : — Ptggura and Gleno- 

 pliora had a simple rotary locomotive organ; Ichthgdium and Chcetonotus, 

 only a long ciliary band upon the ventral surface. Again, the two foimer 

 had a simple foot-like process, and evident oesophageal teeth ; the two latter 

 a forked tail and no visible teeth. Dujardin, who has given a very good 

 account of (Jlicetonotus, rejected that genus, together with Ichthgdium, from 

 among the Rotatoria, and placed the two in a sort of subfamily of Ciliated 

 Protozoa, under the name of ' Symmetrical Infusoria.' Of the other two 

 genera, Glenophora and Ptggura, he ignored altogether the former, and 

 transposed the latter to his family of ' Melicertiens.^ Since the date of his 

 systematic treatise (Hist, des Infus. 1841), he has sketched the histoiy of a 

 genus under the name of EUimoderia, which is evidently allied to Chcetonotus 

 (A. S. N. XV. p. 158). 



